Where does “bitter” come from?

bitter (Middle English) comes from Old English bitter, from Old English biter, from Old Norse bitr, from Proto-Germanic bitraz, from Proto-Indo-European bʰidrós — biting, splitting.

Ancestry of “bitter”, step by step

StepLanguageWordMeaning
1Old EnglishbitterAlternative form of biter
2Old Englishbiterbitter; bitter, severe, painful, biting
3Old Norsebitrbitter
4Proto-Germanicbitrazbitter
5Proto-Indo-Europeanbʰidrósbiting, splitting
Every word from Proto-Indo-European bʰidrós →Every word from Proto-Germanic bitraz →Every word from Old Norse bitr →